Determine Whether the Given Function Is One-To-One $f ( x ) = x ^ { 2 } - 7$

Multiple Choice

Determine whether the given function is one-to-one. If it is one-to-one, find its inverse function.
- $f ( x ) = x ^ { 2 } - 7$

A) $\mathrm { f } ^ { - 1 } ( \mathrm { x } ) = \mathrm { x } ^ { 2 } + 7$
B) $f ^ { - 1 } ( x ) = x ^ { 2 } - 7$
C) $\mathrm { f } ^ { - 1 } ( \mathrm { x } ) = \mathrm { x } + 7$
D) not a one-to-one function